The seat — designed so they could work inside vehicles on the assembly line with less strain — was designed with the help of workers, who had aching backs and sore joints from their work, the Detroit Free Press reported Tuesday.

On the assembly line recently, Aaron Ellington, 39, used the Happy Seat to slide into vehicles. In the past, such work was tough for Ellington, who is slightly taller than 6 feet and weighs 270 pounds.

"It was a pain the back," he said. The Happy Seat "beats having to lean into the car."

The Happy Seat is one of a handful of changes designed to make jobs easier, injuries rarer and quality better at the plant, which makes the Sebring sedan and convertible for DaimlerChrysler AG's Chrysler Group.

Workers advised engineers and company officials to craft tools for the plant, such as a device called the Spider Fixture, which has tentacles to reach across an open convertible body and measure the glass fit.